1. Field of the Invention
The present invention relates to a rotary wheel, a light source unit, a projector and a rotary wheel fabrication method.
2. Description of the Related Art
In these days, data projectors are used on many occasions as image projection units which project images including images of screens of personal computers and video images, as well as images based on image data which are stored in memory cards on to a screen. In these projectors, light emitted from a light source is collected on to a micromirror display element called a digital micromirror device (DMD) or a liquid crystal panel for projection of color images on to a screen.
Additionally, in association with propagation of personal computers and audio equipment such as DVD players and the like, such projectors have been finding a variety of applications from use for business presentations to domestic use. Conventionally, the mainstream of these projectors has been those which utilize a high-intensity discharge lamp as a light source. In recent years, however, there have been made many developments and proposals on data projectors which use, as a light source, a semiconductor light emitting diode such as a laser diode.
For example, there are proposed a light source unit which includes an excitation light source which employs laser diodes to emit light of blue wavelength band and a luminescent wheel (a rotary plate) which has a luminescent material layer adapted to absorb light emitted from the excitation light source to transform the excitation light into visible light and which is driven to rotate by a motor and a projector which employs this light source unit.
Japanese Unexamined Patent Application No. 2004-197922 (Patent Literature 1) discloses a vibration preventive system for suppressing the vibration of a rotary disc such as a color wheel by evening the weight balance of the rotary disc when it is rotating in which a curable liquid is accommodated in a dish-like vessel which is provided on the rotary disc so as to eliminate vibrations of the rotary disc in an effective fashion.
In the proposal described in Patent Literature 1, however, there is provided a member made up of a hub which is a dish-like vessel and to which the color wheel is connected at a distal end of a rotary shaft, and an adhesive is injected onto the hub. According to this configuration, the number of components involved is increased, and the number of fabrication steps is also increased, leading to an increase in fabrication costs.
Additionally, according to the configuration in which the hub is so provided, in disposing a lens unit which is made up of a collective lens which collects excitation light to an excitation light source side of the color wheel efficiently and other lenses, spaces for the lens unit and the hub have to be ensured, leading to a problem that the light source unit and hence the projector are enlarged in size.